JPH08184283A - Advanced excavation work of guide tunnel in side wall - Google Patents

Abstract

PURPOSE: To dispense with overbreak, by excavating advanced guide tunnels so as to make vertically long elliptical forms so that the advanced guide tunnels are superposed with the main tunnel side wall in the peripheral lines. CONSTITUTION: Vertically long elliptic advanced guide tunnels 21, 22 inscribing a part of the lower part of the side wall so as to superpose with each other in the peripheral line, are excavated at the lower positions of both side walls of the main tunnel 20 section. The excavated tunnel 1 is supported to form a ring along the circumstance of the tunnel wall by H-shaped steels and protected by sprayed concrete on the wall face. Thereafter, on excavating the main tunnel, the space between the upper ends of both side walls of the superposed parts of the main tunnel side walls is supported by H-shaped steel members or wound with segments 4, while the segments or supports of the advanced guide tunnels 21, 22 are re moved or cut with muck in parallel with excavation of the upper half. Subsequently, on constructing the main tunnel invert in excavation of the lower half, the H-shaped members of the advanced tunnels are used or concrete is placed between the lower ends of both side walls of segments or PC concrete slabs are laid down. In this way, the side walls of the main tunnel are used in common at the superposed part with the advanced tunnels and only the upper part and the lower invert part as the rest may be excavated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tunnel construction method, and more particularly, to a sidewall guideway advanced construction method for advancing a guideway before the main shaft construction.

[0002]

2. Description of the Related Art As a technique for constructing a side wall tunnel, a sheet pile method, a mountain construction method by NATM (New Austrian tunneling method), and a TBM with a circular tunnel section are used.
There are two possible construction methods, the (tunnel boring machine) construction method.

In the case of a side wall tunnel by TBM, as shown in FIG. 7, first, a circular advanced tunnel 51 is excavated at the lower portions of both side walls of the tunnel section which becomes the main tunnel 50. That is, in this method, the advanced tunnel is excavated in the lower part of the side wall of the main shaft so that the overexcavation (hatching point) is about half of the excavation section, and the concrete wall 52 facing the excavation point
The construction of the main tunnel 50 with the designed cross section is performed by building an arched H steel and supporting concrete by spraying concrete on these concrete walls, in addition to this, striking rock bolts 54 for ground improvement. .

[0004]

However, in the case of the side wall digging advanced by the above-mentioned mountain construction method, although the tunnel cross-sectional shape is arbitrary, the excavation efficiency is lower than that of the TBM,
It is necessary to place concrete walls that form the basis of arch-shaped supports spanning the walls on both sides of the advanced tunnel, and the construction period of this formwork and curing will prolong the construction period. The amount of waste and the amount of concrete used have increased, and the method is now inefficient.

Therefore, in the case of the side wall mine advanced by the TBM method, since the cutter surface of the TBM is circular, a considerable part of the cross section of the main mine is overexposed, or if it is temporarily laid inside the main pit. Even when excavating in contact, the advanced guideway is inscribed at a point with respect to the main shaft, so the advanced guideway cannot also serve as the main shaft support, and the effectiveness as the advanced guideway cannot be expected.

The present invention is intended to solve the above-mentioned drawbacks of the conventional method, and its purpose is to improve the excavation efficiency and ensure the safety, or the TBM method or the shield method, or a full-scale method that combines these methods. The shield TBM method is adopted, and the side wall digging advanced method with the amount of excess digging lower than these conventional methods is provided.

Another object of the present invention is to reduce the amount of excavation by excavating an advanced guideway that is inscribed linearly instead of a point with respect to the section of the main shaft. The side wall tunnel advanced construction method, which can be used as part of the support or lining of the main pit, will be provided.

[0008]

The present invention has been made based on the above object, and the gist thereof is to excavate an advanced tunnel near the side wall of the tunnel section of the main shaft before excavating the main shaft. In the sidewall guideway advanced construction method, the advanced guideway is excavated into a vertically elongated elliptical cross section so that the side wall portion of the advanced guideway and the side wall section of the main shaft are inscribed and linearly overlap each other. It is in the advanced method of side wall tunneling.

As for the method of excavating the above-mentioned advanced tunnel or main shaft, if it is a machine excavation, there is no limitation on the type of method such as the mountain construction method represented by TBM, NATM or the shield construction method. A method of excavating the tunnel cross section as a vertically elongated elliptical shape by inclining either the left or right of the circular cutter surface of the shield TBM (which also serves as a shield machine for the TBM) is suitable.

In addition, the fact that the overlapping portions on both side walls of the advanced tunnel and the main tunnel are linear means that when the large circle is inscribed in the small circle, it is point contact, but it is an ellipse into a substantially large circle. It is shown that when the small circle of the shape is inscribed, the overlapping part becomes linear, and the main shaft is excavated with this linearly overlapping part.

Another feature of the present invention is that the excavation of the advanced tunnel also serves as a part of the side wall support of the main shaft for excavating the lateral overlapping portion of the shaft. is there.

Still another feature of the present invention is that the excavation of the advanced tunnel also serves as a part of the side wall lining of the main tunnel which is subsequently excavated for the lining of the side overlapped portion of the tunnel. .

[0013]

In the present invention, first, an advanced tunnel having a vertically elongated elliptical cross section is excavated in a linearly overlapped state in the lower part of the side wall of the main tunnel of the design, and connected between the superposed upper ends of the advanced tunnel. , By supporting or lining the main pit, the excess digging of the main pit should be eliminated as much as possible so that a part of the advanced guide pit or lining also serves as a part of the main pit.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An outline of a TBM as an example used in the present invention will be described below with reference to FIGS.

A large number of cutting cutters 2 are arranged on the cutter surface 1 of the TBM (arrow A), and this surface is inclined by an angle θ to the left by a cutter drum 3 rotated by an electric motor 6 as shown in the plan view. , It is possible to excavate an advanced tunnel with an oval cross section.

The cutter head support 7 at the rear part of the cutter drum 3 can be expanded and contracted on the left and right sides by hydraulic cylinders 12 and 13, and the supports 14 and 15 are pressed against the pit wall by the extension thereof. 1
By adjusting the pressure contact forces of 4 and 15 by automatic control, tilting the cutter head to excavate the cutter head and suppressing the displacement of the cutter head in the left-right direction, the tunnel alignment is kept constant.

A gripper 8 is connected to the main beam 11 with thrust jacks 4 and 5 interposed therebetween, and the gripper 8 can be expanded and contracted by a gripper jack 9.

On the other hand, in the box-shaped main beam 11, a belt conveyor (not shown) for transporting the excavation gap is arranged in a groove shape.

A roof support 17 is provided above the cutter head support 7 via a hydraulic cylinder 16 to prevent the TBM excavation from bending up and down.

The side wall tunneling advanced method of the present invention, which uses the TBM having the above structure, will be described below.

First, before construction is carried out along a relatively large-diameter main tunnel tunnel planned route as a roadway of two or more lanes or a route, at a location which becomes lower parts of both side walls of the tunnel section of the main tunnel 20, The vertically elongated elliptical advanced tunnels 21 and 22 are inscribed so as to linearly overlap with a part of the lower portion of the side wall.

When excavating, the gripper jack 9 is extended to press the gripper 8 against the pit wall 19 to take a reaction force,
The cutter face 1 is pressed against the face by the extension force of the thrust jacks 4 and 5, and the tunnel is advanced while the cutter drum 3 is rotated by the electric motor 6. Thrust jack 4,
When 5 extends by one stroke, excavation is interrupted, the rear support 10 is extended and grounded, the gripper 8 is contracted, and then the thrust jacks 4 and 5 that are extended are contracted to advance the gripper 8. Then, the gripper 8 is extended again and pressed against the pit wall 19, and then the cutter drum 3 is rotated to advance.

The excavated slit is scooped up by the cutter drum 3 and the tip thereof is located inside the drum.
It drops onto the corrugated conveyor 11 and is discharged to the rear of the tunnel.

In the excavated tunnel (shown in FIG. 1), H steel is supported in a ring shape along the circumference of the pit wall 19 by a supporting erector (not shown), and then the pit wall containing H steel. Spray concrete onto. Depending on the property of the tunnel ground, instead of concrete spraying, the segment is wound in the tunnel circumferential direction by an erector (not shown) (in FIG. 1).

After that, when excavating the main shaft, the upper half part is excavated (FIG. 1), but according to this excavation, the segments or supports of the advanced tunnels 21 and 22 are removed or they are cut together with the slit. Meanwhile, the H steel 23 is used to support the upper ends of the both side walls of the portion that overlaps the side wall of the main shaft 20 or the segment 24 is wound (FIG. 1, FIG. 6 or FIG. 5).

Subsequently, the lower half of the main shaft is excavated. In this case, the main shaft invert construction is carried out by using the H steel of the above-mentioned advanced shaft,
This is done by placing concrete between the lower ends of both side walls of the segment 24 or by laying a PC concrete slab (see FIG. 1).

In this way, the side wall portion of the main shaft 20 is also used as a portion that overlaps with the advanced guide shaft 21, and the rest only needs to be constructed by the upper and lower inverts of the main shaft.

It is also possible to carry out secondary lining with concrete from the support with the H steel and sprayed concrete, or the support with segments.

[0029]

As described above, in the method of the present invention having the above structure, the advanced tunnel and the side wall of the main tunnel are linearly overlapped in the tunnel circumferential direction, and therefore the following effects can be expected. .

A part of the advanced tunnel and the excavation line on the side wall of the main tunnel can be aligned linearly, and excavation loss (excess excavation for securing the bottom plate width) does not occur.

It is economical because part of the guide shaft support (spraying + steel support or segment) can also be used as the main shaft side wall support.

With the conventional TBM, the advanced tunnel shown in FIG. 7 is excavated, and the concrete wall 52 is constructed in the excavated portion,
As in the case of assembling the support on the upper part of the concrete wall 52, the final structure such as the contact portion between the concrete wall 52 and the support does not have stress concentration, and the structure is stable. In addition, TB
M's rapid workability can be exhibited, and machine excavation improves safety against skin loss.

[Brief description of drawings]

FIG. 1 is an explanatory view of a tunnel cross section showing a construction means of a method of the present invention.

FIG. 2 is a schematic side view of a TBM used in the method of the present invention.

FIG. 3 is a plan view of FIG.

FIG. 4 is a front view of the cutter drum of FIGS. 2 and 3.

FIG. 5 is an explanatory view showing a state in which a part (segment) of the advanced tunnel in the method of the present invention is also used as a part of the main shaft support.

FIG. 6 is a partial explanatory view showing an example in which the main shaft is supported above the advanced tunnel segment.

FIG. 7 is an explanatory view of a tunnel cross section of a conventional sidewall digging advanced method.

[Explanation of symbols]

 A TBM 1 Cutter surface 4, 5 Thrust jack 6 Electric motor 7 Cutter head support 8 Gripper 10 Rear support 19 Advanced tunnel shaft wall 20 Main shaft 21, 22 Advanced shaft ~ Procedure of the method of the present invention

 ─────────────────────────────────────────────────── ─── Continued Front Page (71) Applicant 000201478 Maeda Construction Co., Ltd. 2-1026 Fujimi, 2-chome, Chiyoda-ku, Tokyo (72) Inventor Takashi Sakai 2-10-2 Otowa NS Bunkyo-ku, Tokyo Otowa NS Building 7F Inside Advanced Technology Center (72) Inventor Mitsuro Higo 2-5-8 Kitaoaoyama, Minato-ku, Tokyo Incorporation (72) Inventor Yoshiaki Ishida 4-12-20 Nihonbashihoncho, Chuo-ku, Tokyo Sato Industry Co., Ltd. (72) Inventor Masaru Nakamura 3-1-1 Ueno, Hirakata-shi, Osaka Komatsu Ltd. Osaka Plant (72) Teruo Sakai, Fujimi 2-1026, Chiyoda-ku, Tokyo Maeda Construction Industry Co., Ltd.

Claims (3)

[Claims] 1. A sidewall guideway advanced construction method for excavating an advanced guideway near a sidewall of a tunnel cross section of the main shaft before excavating the main shaft, wherein a side wall portion of the advanced guide shaft and a side wall portion of the main shaft are respectively formed. A method for advanced side wall pit construction, wherein the advanced pit is excavated in a vertically elongated elliptical cross-section so that the side wall cross-sections of the above are substantially inscribed and polymerized linearly. 2. The support of the side overlapped portion of the advanced tunnel by excavation is also used as a part of the side wall support of the main tunnel to be excavated later. Described side wall mine advanced construction method. 3. The lining of the side overlapped portion of the advanced tunnel due to excavation of the advanced tunnel also serves as a part of the side wall lining of the main pit to be subsequently drilled. The advanced method of side wall tunneling described in.